Electric motor driven adjustable support apparatuses for supporting a mattress are generally known. The known support apparatuses have support parts that are adjustable relative to one another by means of an electric motor driven drive apparatus. The known support apparatuses are generally adjustable between a reclined position, in which the support parts together form an essentially horizontal support plane, and a sitting position, in which the support parts are adjusted relative to one another and support a user resting on the mattress, at least in the area of his/her back, to facilitate sitting on the mattress, for example in the bed. The number of support parts of the support apparatus may vary, depending on the particular requirements. The support apparatuses generally have at least one middle support part that is stationary during the adjustment, and an upper body support part that is adjustable relative to the middle support part. The upper body support part itself may have a multi-part design, and may have a back support part and a head and neck support part, for example. Depending on the particular requirements, in addition to the upper body support part a lower body support part may be provided, which at its end facing away from the upper body support part is connected to the middle support part. The lower body support part may also have a multi-part design, and may have a thigh support part and a calf support part, for example.